101 citations · 575 across the 21 of their papers we have counts for
21 papers
Ethane and methane at high pressures: structure and stability
Elissaios Stavrou, Alexander A. Maryewski, Sergey Lobanov +4
We have performed a combined experimental and theoretical study of ethane and methane at high pressures up to 120 GPa at 300 K using x-ray diffraction and Raman spectroscopy and th…
Polymorphism of superionic ice
Vitali B. Prakapenka, Nicholas Holtgrewe, Sergey S. Lobanov +1
Water is abundant in natural environments but the form it resides in planetary interiors remains uncertain. We report combined synchrotron X-ray diffraction and optical spectroscop…
Low thermal conductivity of iron-silicon alloys at Earth core conditions with implications for the geodynamo
Wen-Pin Hsieh, Alexander F. Goncharov, Stéphane Labrosse +5
Earth core is composed of iron (Fe) alloyed with light elements, e.g., silicon (Si). Its thermal conductivity critically affects Earth thermal structure, evolution, and dynamics, a…
Blocked radiative heat transport in the hot pyrolitic lower mantle
Sergey S. Lobanov, Nicholas Holtgrewe, Gen Ito +8
The heat flux across the core-mantle boundary (QCMB) is the key parameter to understand the Earth/s thermal history and evolution. Mineralogical constraints of the QCMB require dec…
Opaque Lowermost Mantle
Sergey S. Lobanov, François Soubiran, Nicholas Holtgrewe +3
Earth/s lowermost mantle displays complex geological structures that likely result from heterogeneous thermal and electromagnetic interaction with the core. Geophysical models of t…
Insulator-metal transition in liquid hydrogen and deuterium
Shuqing Jiang, Nicholas Holtgrewe, Zachary M. Geballe +4
The insulator-to-metal transition in dense fluid hydrogen is an essential phenomenon to understand gas giant planetary interiors and the physical and chemical behavior of highly co…
Observation of a metastable intermediate during solid-solid phase transformation in response to rapid compression
Michael R. Armstrong, Harry B. Radousky, Ryan A. Austin +23
In order to probe the mechanism of solid-solid phase transformations, we have applied ultrafast shock wave compression (120 picosecond duration) and ultrashort (130 femtosecond) x-…
Metallization and molecular dissociation of dense fluid nitrogen
Shuqing Jiang, Nicholas Holtgrewe, Sergey S. Lobanov +4
Diatomic nitrogen is an archetypal molecular system known for its exceptional stability and complex behavior at high pressures and temperatures, including rich solid polymorphism,…
Uranium polyhydrides at moderate pressures: prediction, synthesis, and expected superconductivity
Ivan A. Kruglov, Alexander G. Kvashnin, Alexander F. Goncharov +7
Hydrogen-rich hydrides attract great attention due to recent theoretical (1) and then experimental discovery of record high-temperature superconductivity in H3S (Tc = 203 K at 155…
Synthesis of Xenon and Iron/Nickel intermetallic compounds at Earth's core thermodynamic conditions
Elissaios Stavrou, Yansun Yao, Alexander F. Goncharov +5
Although Xe is known to form stable compounds with strong electronegative elements, evidence on the formation of stable compounds with electropositive elements, such as Fe and Ni,…
Raman spectroscopy and X-ray diffraction of sp3-CaCO3 at lower mantle pressures
Sergey S. Lobanov, Xiao Dong, Naira S. Martirosyan +8
The exceptional ability of carbon to form sp2 and sp3 bonding states leads to a great structural and chemical diversity of carbon-bearing phases at non-ambient conditions. Here we…
Stable high-pressure phases in the H-S system determined by chemically reacting hydrogen and sulfur
Alexander F. Goncharov, Sergey S. Lobanov, Vitali B. Prakapenka +1
Synchrotron X-ray diffraction and Raman spectroscopy have been used to study chemical reactions of molecular hydrogen (H2) with sulfur (S) at high pressures. We find theoretically…
Optical signatures of low spin Fe3+: a new probe for the spin state of bridgmanite and post-perovskite
Sergey S. Lobanov, Han Hsu, Jung-Fu Lin +2
Iron spin transition directly affects properties of lower mantle minerals and can thus alter geophysical and geochemical characteristics of the deep Earth. While the spin transitio…
Radiative conductivity and abundance of post-perovskite in the lowermost mantle
Sergey S. Lobanov, Nicholas Holtgrewe, Jung-Fu Lin +1
Thermal conductivity of the lowermost mantle governs the heat flow out of the core energizing planetary-scale geological processes. Yet, there are no direct experimental measuremen…
Hydrogen sulfide at high pressure: change in stoichiometry
Alexander F. Goncharov, Sergey Lobanov, Ivan Kruglov +5
Hydrogen-sulfide (H2S) was studied by x-ray synchrotron diffraction (XRD) and Raman spectroscopy up to 150 GPa at 180-295 K and by quantum-mechanical variable-composition evolution…
Reduced radiative conductivity of high and low spin FeO6 octahedra in the Earth's lower mantle
Sergey S. Lobanov, Nicholas Holtgrewe, Alexander F. Goncharov
The ability of Earths mantle to conduct heat by radiation is determined by optical properties of mantle phases. Optical properties of mantle minerals at high pressure are accessibl…
Pressure, stress, and strain distribution in the double-stage diamond anvil cell
Sergey S. Lobanov, Vitali B. Prakapenka, Clemens Prescher +5
Double stage diamond anvil cells (DAC) of two designs have been assembled and tested. We used a standard symmetric DAC as a primary stage and CVD microanvils machined by a focused…
Stable magnesium peroxide at high pressure
Sergey S. Lobanov, Qiang Zhu, Nicholas Holtgrewe +4
Rocky planets are thought to comprise compounds of Mg and O as these are among the most abundant elements, but knowledge of their stable phases may be incomplete. MgO is known to b…
Synthesis of ultra-incompressible sp3-hybridized carbon nitride
Elissaios Stavrou, Sergey Lobanov, Huafeng Dong +4
Search of materials with C-N composition hold a great promise in creating materials which would rival diamond in hardness due to the very strong and relatively low-ionic C-N bond.…
Backbone NxH Compounds at High Pressures
Alexander F. Goncharov, Nicholas Holtgrewe, Guangrui Qian +11
Optical and synchrotron x-ray diffraction diamond anvil cell experiments have been combined with first principles theoretical structure predictions to investigate mixed N2 and H2 u…
Stability of numerous novel potassium chlorides at high pressure
Weiwei Zhang, Artem R. Oganov
K-Cl is a simple system displaying all four main types of bonding, as it contains (i) metallic potassium, (ii) elemental chlorine made of covalently bonded Cl2 molecules held toget…